Summarized Consolidating Income Statements (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 28, 2012	Sep. 30, 2011	Sep. 28, 2012	Sep. 30, 2011
Consolidated Income Statement
Revenue	$ 2,894	$ 2,963	$ 8,872	$ 8,792
Expense	2,040	2,085	6,219	6,215
Operating Income	854	878	2,653	2,577
Equity in Earnings of Subsidiaries	0	0	0	0
Interest (Expense) / Benefit	(138)	(138)	(421)	(412)
Other Income - Net	5	6	14	11
Earnings Before Income Taxes	721	746	2,246	2,176
Income Tax (Expense) / Benefit	(266)	(282)	(830)	(811)
Net Earnings	455	464	1,416	1,365
Total Comprehensive Earnings	471	473	1,458	1,398
CSX Corporation [Member]
Consolidated Income Statement
Revenue	0	0	0	0
Expense	(90)	(77)	(266)	(210)
Operating Income	90	77	266	210
Equity in Earnings of Subsidiaries	478	500	1,512	1,472
Interest (Expense) / Benefit	(126)	(123)	(381)	(370)
Other Income - Net	(1)	0	(3)	3
Earnings Before Income Taxes	441	454	1,394	1,315
Income Tax (Expense) / Benefit	14	10	22	50
Net Earnings	455	464	1,416	1,365
Total Comprehensive Earnings	471	473	1,458	1,398
CSX Transportation [Member]
Consolidated Income Statement
Revenue	2,878	2,946	8,823	8,743
Expense	2,166	2,220	6,587	6,584
Operating Income	712	726	2,236	2,159
Equity in Earnings of Subsidiaries	0	(1)	(1)	2
Interest (Expense) / Benefit	(17)	(19)	(53)	(64)
Other Income - Net	2	6	6	8
Earnings Before Income Taxes	697	712	2,188	2,105
Income Tax (Expense) / Benefit	(262)	(266)	(795)	(782)
Net Earnings	435	446	1,393	1,323
Total Comprehensive Earnings	437	448	1,393	1,325
Eliminations and Other [Member]
Consolidated Income Statement
Revenue	16	17	49	49
Expense	(36)	(58)	(102)	(159)
Operating Income	52	75	151	208
Equity in Earnings of Subsidiaries	(478)	(499)	(1,511)	(1,474)
Interest (Expense) / Benefit	5	4	13	22
Other Income - Net	4	0	11	0
Earnings Before Income Taxes	(417)	(420)	(1,336)	(1,244)
Income Tax (Expense) / Benefit	(18)	(26)	(57)	(79)
Net Earnings	(435)	(446)	(1,393)	(1,323)
Total Comprehensive Earnings	$ (437)	$ (448)	$ (1,393)	$ (1,325)